MSD 3712 Iridium Spark Plug 1IR5L Single - 14mm Shorty High Performance

The MSD 3712 Iridium Spark Plug (1IR5L) is a single, shorty-style performance spark plug engineered from the inside out to maximize combustion efficiency and deliver exceptional durability under demanding conditions. Designed specifically for high-output ignition systems, this plug is ideal for street performance, road racing, and off-road applications.

Key Features:

• Iridium center tip — A super-hard iridium tip promotes the strongest, most consistent spark while resisting wear over millions of ignition cycles
• Proprietary ceramic insulator — MSD's exclusive ceramic blend delivers the highest dielectric strength available, forcing the spark across the plug gap even under extreme cylinder pressures
• Yttrium-enhanced machined ground electrode — The machine-ground strap treated with Yttrium withstands the intense heat generated by high-horsepower ignitions and reduces the risk of pre-ignition
• Copper center core — A proprietary copper core efficiently transfers heat away from the plug to the cylinder head, helping prevent knock and extending insulator tip life
• Projected tip design — The machined electrode exposes more surface area to incoming air-fuel gases, promoting the most complete combustion event possible
• Shorty-style housing — Compact form factor designed for applications where header or engine bay clearance is limited
• 14mm thread, tapered seat — Standard fitment with a 0.691 in. reach and resistor construction for compatibility with modern ignition systems
• 100% tested before packaging — Every plug is tested prior to shipping to ensure consistent quality
• Legal for sale and use on emissions-controlled vehicles (1966 and newer U.S. vehicles) when used per the manufacturer's application guide

Sold individually. Part number designation: 1IR5L. Whether you're pushing the limits at the track or demanding reliable performance on the street, the MSD 3712 iridium spark plug is built to outperform and outlast conventional performance plugs.